I feel like workers ruin too many strategic possibilities in this game and make the gameplay pretty lame. Their ability to tie up ranged units and deny shield generator damage is an enormous part of the meta, and they seem very imbalanced in their ability to do so.
In the early game SM seem to have a large advantage with faster servitors that close the distance more quickly to their targets, combined with the 450 shield HP that they get from the standard, turning them into 750 HP ranged-disruption monsters. This seems to greatly reduces the viability of early ranged units as part of a strategy.
Another one is obviously the bonesinger teleport. Between increased speed, stealth ability, and a teleport, they are all very imbalanced in their ability to tie up ranged units.
A few Heavy weapons/ranged squads would be a viable means to defend a power core or resource from shadow specter harass or early game elite harass in themselves, but teleporting bonesingers completely nullifies these options as viable, requiring your opponents to leave a significant portion of your army defending their objectives if they want to push your points. This is made even more difficult when elites like Kyre come into play, who are great at taking out defenses and are tough to kill.
From my understanding, Eldar have the greatest range on their grenades, and they also have some pretty good snipers. The bonesinger teleport seems over the top in their ability to deal with lootas and to a lesser extent shootas which are vital to defend against the early game DA harass which still seems effective vs ork.
Another thing that is really annoying is when you are trying to kill your opponents shield generators and they run their workers around inside the shield to deny damage, so you end up chasing their workers around instead of doing much damage, and the worker runs to the turret or teleports away only to be replaced by another worker when it gets low.
I feel like the game would be much better served by removing worker shenanigans that further imbalance and limits strategic possibilities in the game and make it annoying rather than the neato factor it provides from having them be so different.